Mr Abbott, a firm backer of the yes case along with other government leaders, said he hoped that naming a date would help crystallise the discussion and lead to a form of words capable of drawing majority support among Australian voters.

"I am determined that we will soon set a date for the referendum and I am determined that we should try as hard as we humanly can to conduct the referendum discussion in a constructive way, that we should try to avoid the kind of high-pitched shouting which sometimes mars public debates in this country," Mr Abbott told reporters.

"Over recent months and weeks we have managed to have, I think, a very constructive bipartisanship on national security (and) for some years now we have been able to avoid a hyper-partisanship indigenous affairs and I want that to continue in the weeks and months and years ahead."

The step forward came amid a mostly procedural meeting of the nation's governments from which few concrete decisions emerged.

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Among those was a commitment from the Commonwealth to establish a single federal agency to steer hopeful parents of adopted children through Commonwealth agencies.

"At the moment, if you want to adopt, you typically go to a state adoption agency, you consider the issue generally and at some point, often enough, you will decide that you are going to have a go at overseas adoption because that is more prospective than local adoption," Mr Abbott said.

"Then, as things stand, you have got to navigate largely unaided a thicket of Commonwealth agencies," he said. "What we want to establish is a Commonwealth agency, it might be a governmental agency or it might be an NGO but a Commonwealth agency, one way or another, that will basically take people by the hand and lead them from agency to agency, lead them through the process of getting the relevant approvals for overseas adoption so that it can happen more quickly."

Another issue of concern to the leaders was a shock decision of China's cabinet to suddenly re-apply import tariffs on Australian coal - a decision which could lead to lower exports and potentially the loss of jobs and closure of marginal mines in Australia.

Mr Abbott, whose government is locked in the final stages of nine-year free trade talks with Beijing, tried to tread a diplomatic line, condemning the tariffs as "the kind of hiccup in our biggest and most important trading relationship that we just don't want or need," but also denying it had become a new sticking point in those talks.

He said he had spoken to Trade Minister Andrew Robb but not since the tariff was announced on Thursday. "When I last spoke to Andrew Robb about this and that was a few days ago because I haven't had a chance to talk to him about this particular issue, he was confident that things were on track," he said.